Description:The EAITRDA7 consist of an infrared emitting diode and an NPN silicon phototransistor, encased side-by-side on converging optical axis in a black Thermoplastic Housing. The phototransistor receives radiation from the IR LED only .This is the normal Situation. But when an object is in between , phototransistor could not receives the radiation.For additional component information , please refer to IR204 and PT204-6B